Chapter 7 Exit quiz

Photosystem II (PSII) inhibitors are a class of herbicides that work by blocking a key step of the light-dependent reactions, eventually shutting down the pathway completely.

Which products of photosynthesis would not be produced as a result of this herbicide?

• ATP only

• Sunlight, water, and carbon dioxide

• ATP and sugars

• Sugars only

The cytochrome b₆f complex is an integral thylakoid membrane protein that forms an electrochemical gradient by pumping protons. In an experiment, researchers apply a toxin to a plant cell that inhibits the cytochrome b₆f complex.

Which of the following explains the most likely effect of this toxin on the light reactions of photosynthesis?

• Hydrogen ions will move across the thylakoid membrane using simple diffusion.

• NADP+ will not be reduced to NADPH.

• ATP synthesis will not occur.

• Carbohydrates will not be produced in the stroma.

Which of the following best explains how the light reactions of photosynthesis generate ATP?

• A proton gradient drives the formation of ATP from ADP and inorganic phosphate via ATP synthase.

• Energy from light excites ATP synthase, causing it to bind ADP with inorganic phosphate to form ATP.

Which of the following best describes how the Calvin cycle and the light reactions of photosynthesis function together?

• The Calvin cycle generates ATP and NADPH to excite electrons during the light reactions.

• The Calvin cycle uses ATP and NADPH generated by the light reactions to break down carbohydrates.

• The Calvin cycle produces ATP and NADPH to drive the formation of an electrochemical gradient during the light reactions.

• The Calvin cycle uses ATP and NADPH generated by the light reactions to synthesize carbohydrates.

The oxygen produced in photosynthesis comes from what molecule?

• glucose

• P680

• water

• ATP

When a photon of light energy reaches a reaction center chlorophyll molecule, what becomes excited?

• A molecule of water vapor

• An electron

• a carbon dioxide molecule

• an atom of oxygen

C4 Plants separate carbon fixation by ______, while CAM plants separate carbon fixation by _____.

• Day, Night

• Location, Time

• Bundle Sheath Cells, Mesophyll Cells

• Night, Location

During the light reactions, H+ is pumped from the _____ to the _____ in order to help ATP Synthase.

• Lumen, Thylakoid

• Stroma, Granum

• Lumen, Stroma

• Inner Membrane Space, Lumen

Which of the following is made via Chemiosmosis during Photosynthesis?

• ATP

• Oxygen

• Water

• Glucose

Which of the following occurs during the Calvin cycle?

• formation of G3P

• reduction of NADP+

• release of oxygen

• Generation of CO2